Well, I think it's time for rampant speculation on what this "bonus feature" is... hm....
The best I can come up with atm is there being more than one solar system and the ability to travel between them. That seems highly unlikely, so sufficiently rampant speculation, I feel.
More realistically, I'm going to guess the ability to perform missions for the different factions and the ability to improve relations with factions as a result. Just a few to start with, but progressively more as the updates continue over the months.